Disk laser is a kind of all solid-state laser, which has been developing rapidly since 1994 when Adolf. Giesen et al. first invented the disk laser. Disk laser uses disk-like material as gain medium, i.e. disk gain medium, wherein the disk-like material is small in thickness and is relatively large in transverse dimension, in operation, disk laser needs to dissipate the heat of the disk gain medium. A traditional cooling system of disk gain medium includes copper heat sink, which is attached to the disk gain medium and has high thermal conductivity. Copper heat sink is provided with cooling medium microchannels. Because the region of the disk gain medium is very big and the thickness is very small, therefore the heat of the gain medium could be transferred to the cooling medium micro channels quickly and effectively, and then taken away by the cooling medium. Disk laser has some advantages, for example, disk laser can export the heat deposition in the gain medium efficiently, and reduce the thermal lens effect of the gain medium, and therefore, it is possible to achieve high power, high efficiency, and high beam quality laser output. As the disk laser has the above-mentioned advantages, thus it is widely used in national defense and military affairs, scientific research, industry manufacturing and various regions.
However, when the disk laser is in operation, the heat loaded into the disk gain medium causes the temperature of the gain medium into Gaussian distribution, i.e., the energy density in the center of the disk gain medium is relatively high, and the energy density gradually reduced from the center to the surrounding portion. As a result, the center portion of the disk gain medium has a relatively large outward expansion, and an upside-down bowl-like deformation is formed, and this is the heat lens effect of the disk laser. When disk laser is operated in high power, the heat lens effect of the disk gain medium will affect the laser output power, output stability and beam quality of the laser. If the expansion deformation of the disk gain medium exceeds the material's capability, it may even result in a disk gain medium burst.